Abstract: An adaptive controller is provided for controlling the velocity of a ram in an injection molding apparatus during the injection stage of the molding cycle. The controller includes two sets of parameters. The first set define an open-loop control equation for controlling the ram velocity. The second set of parameters define a closed-loop control equation for controlling the ram velocity. Control of the ram, during the injection stage, is partitioned into discrete segments, wherein the open-loop control equation governs during the first portion of each segment, and the closed-loop equation governs during the latter portion of each segment. Both control equations are designed to drive the ram at a set, target velocity. At the end of each segment, a processor evaluates the actual ram velocity with the set, target velocity. Based upon this evaluation, the first and second set of parameters are modified to improve the ram performance and efficiency on the subsequent injection cycle.

Abstract: An adaptive controller is provided for controlling the transition, in an injection molding apparatus, from the injection stage to the packing stage. The controller operates by controlling the velocity of the ram during the injection stage, and controlling the ram pressure during the packing stage. The controller anticipates the transition from the injection stage to the packing stage by monitoring the ratio of pressure to velocity. The divergence of this ratio forecasts the onset of the packing stage. At this time, a pressure relief valve is preset in anticipation of the packing stage, to prevent a pressure spike during the transition period. The flow control valve is held constant during the transition.